MySQL server has gone away fix

connection_fix.rb

## https://gist.github.com/977188
#
# If your workers are inactive for a long period of time, they'll
# lose their MySQL connection.
#
# This hack ensures we re-connect whenever a connection is lost.
#
# From: https://gist.github.com/238999
#
# Added retrying to prevent infinite loop.
#
module ActiveRecord::ConnectionAdapters
  class MysqlAdapter
    alias_method :execute_without_retry, :execute

    def execute(*args)
      result = execute_without_retry(*args)
      @retrying = false
      result
    rescue ActiveRecord::StatementInvalid, Mysql::Error => e
      if e.message =~ /server has gone away|query: not connected/i
        unless @retrying
          @retrying = true
          warn "Server timed out, retrying"
          reconnect!
          retry
        end
      end
      raise e
    end
  end
end